(1) Field of the Invention
The invention relates to an alignment tool for assembling a rear plate and a frame of a flat display panel, and more particularly to a tool which utilizes an alignment mark having a substantial thickness located on the rear plate to align the rear plate and the frame prior to an adhesion process.
(2) Description of the Prior Art
Referring to FIG. 1, a perspective view of a conventional flat display panel (usually seen in a plasma display) is shown to illustrate the position of a metal frame 3, a glass rear plate 2 and a glass front plate 1. After assembling the front plate 1 and the rear plate 2, the metal frame 3 is overlapped and adhered to a rear surface 22 of the rear plate 2 by a binder, for example, a 3M VHB-type dual-side glue. In practice, the alignment accuracy between the frame 3 and the rear plate 2 is extremely important for the following assembling process of the display panel. The alignment accuracy in between strongly relates to the installation of the electronic elements onto the frame 3 and the electrical connection between the rear plate 2 and the front plate 1 because the electrical connection is usually made by bypassing the sides of the frame 3. In the art, two types of alignment methods are usually used for assembling the rear plate 2 and the frame 3, including a manual aligning method and a mechanical aligning method.
Please refer to FIG. 2 which is a schematic view showing the conventional manual aligning method for assembling the glass rear plate 2 and the metal frame 3. As shown, flat alignment marks 21 without a substantial thickness formed at on the front surface 20 of the rear plate 2. Besides, corresponding alignment notches 31 are formed on the frame 3. A conventional alignment tool 4 having an inspection window 41 is firstly positioned on the rear surface 22 of the rear plate 2 in the manual aligning method, and the inspection window 41 is lying on top of the alignment mark 21. Then, a top protrusion (not shown) of the alignment tool 4 can be used to align with the alignment notch 31 of the frame 3. After the alignment is done, the alignment tool 4 can be removed. The dual-side glue is arranged between the rear plate 2 and the frame 3 in advance, so the frame 3 is then lowered down and adhere to the rear plate 2. Nevertheless, the prior manual aligning method presents following disadvantages.
1. The alignment mark 21 is electroplated on the front surface 20 of the rear plate 2, and the alignment operator observes the mark 21 from the rear surface 22 of the rear plate 2. The visional deviation may occur in the alignment process because the rear plate 2 has a thickness of 3 mm at least in FIG. 2. Therefore, the error in this kind of aligning work has an extended degree of human dependence.
2. Some clamps are usually used to fix the alignment tool 4 and the rear plate 2 in the prior alignment method. The clamp forcing might vary case by case due to some human factors, therefore, breaking or cracking of the rear plate 2 is happened when a undue force is applied. Besides, the position shift between the rear plate 2 and the alignment tool 4 may occur when the clamp force is insufficient.
On the other hand, the mechanical aligning method may waive the human factors so that aforesaid disadvantages can be eliminated. Yet, following restrictions may still be happened in the mechanical aligning method.
1. The cost of the machine is high. Due to a high accuracy, optical automatic positioning mechanism and driving mechanism cannot be substituted by some low-price elements.
2. The machine has a poor suitability. As long as the machine is setup, it is difficult to adjust the machine in time according to different products.
Therefore, a simplified, low-cost, and high accuracy alignment tool should be developed.
Accordingly, it is a primary object of the present invention to provide an alignment tool for assembling a rear plate and a frame of a flat display panel which is simply operated, low-cost, and high precision in aligning the rear plate with the frame.
It is another object of the present invention to provide an alignment tool for assembling a rear plate and a frame of a flat display panel, in which an alignment mark with a substantial thickness is provided to cooperate with an alignment notch so that the aligning operation can be speeded up and aforesaid human factors can be eliminated.
It is a further object of the present invention to provide an alignment tool for assembling a rear plate and a frame of a flat display panel, in which a roller-type fastening mechanism is provided to clamp the rear plate and the alignment tool.
In accordance with the present invention, the alignment tool is operated between the rear plate and the frame during an aligning process. The alignment tool includes a base, a clamp arm and an upper arm. The rear plate includes a front surface, a rear surface opposing to the front surface and adhering with the frame, and an alignment mark formed on the front surface with a predetermined thickness and protruded from the front surface. The base of the alignment tool further includes a base top surface and an alignment notch. The base top surface contacts with the front surface of the rear plate, and the alignment notch has at least two alignment sides to match with the alignment mark.
The clamp arm is protruded from the base of the alignment tool, and the upper arm is protruded from the clamp arm. The upper arm for aligning with the frame has an arm lower surface parallel to and spaced apart from the base top surface by a predetermined distance and forming an open space in between. The arm lower surface contacts with the rear surface of the rear plate during the aligning operation.
In the present invention, the rear plate is sandwiched within the open space between the base top surface and the arm lower surface during the aligning process. The alignment mark is leaned upon the alignment sides of the alignment notch so that the alignment mark is inserted into the alignment notch and the upper arm is positioned in the aperture of the frame. By providing the design of the alignment mark and the alignment notch, the aligning process can be done without eye deviation.
In the present invention, the rear plate can further include a lateral side connecting the front surface and the rear surface, and the alignment tool includes an inner vertical surface adjacent to the open space. The lateral side of the rear plate is positioned next to the inner vertical surface while the inner vertical surface is aligned with the rear plate.
In one embodiment of the present invention, the alignment notch can be formed as a wedge-shaped opening for providing two lateral sides as the alignment sides. In one embodiment of the present invention, the alignment mark includes at least two slanted edges for respectively matching with the alignment sides of the alignment tool and for sliding into the alignment notch during the aligning process.
In another embodiment of the present invention, the frame has an aperture, and the alignment tool includes a base, a clamp arm and an upper arm. The upper arm further includes an arm lower surface and an alignment element, the alignment element can align to the aperture of the frame, and the lower surface is parallel and spaced apart from the base top surface by a predetermined distance and forming an open space in between. The arm lower surface contacts with the rear surface of the rear plate during the aligning process. The upper arm can further include a lower opening and an interior accommodation space for accommodating a fastening mechanism. A portion of the fastening mechanism is exposed from the lower opening. By using the fastening mechanism, the rear plate can be gradually fastened between the the upper arm and the base while the alignment tool is feeding toward the rear plate.
The fastening mechanism can include a roller spaced apart from the arm lower surface a distance. The roller can move along a predetermined track to shorten the distance between the roller and the arm lower surface of the upper arm while feeding the alignment tool toward the rear plate. Furthermore, the roller can rotate by a pivot shaft for moving along the track. The roller can be a wheel, a ball, or any the like. The material for the roller can be a rubber, a plastic material, a cloth, or any compressible material the like.
The fastening mechanism can be a wedge having a narrower end, and the interior accommodation space of the upper arm can be shaped as a wedge-shaped space having a restricted end. The narrower end of the wedge and the restricted end of the wedge-shaped space are located close to the clamp arm so as to gradually fasten the rear plate between the lower surface of the upper arm and the top surface of the base while feeding the alignment tool toward the rear plate. Similarly, the material for the wedge can be a rubber, a plastic material, a cloth, or any resilient material the like.
All these objects are achieved by an alignment tool for assembling a rear plate and a frame of a flat display panel described below.